This application claims the priority of Japanese Patent Application No. 3-325163 filed on Nov. 12, 1991 which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a shutter apparatus for stereoscopic cameras for simultaneously taking a pair of stereoscopic photographs so as to view a subject three-dimensionally.
2. Description of the Related Art
A stereoscopic camera for simultaneously taking a pair of stereoscopic photographs so as to view a subject three-dimensionally is well known. This type of camera is provided with, for example, two photographing lenses which enable the same subject to be taken from rightward and leftward points. The pair of stereoscopic photographs are printed on photographic paper or developed on reversal film (positive film) and viewed through binocular lenses so that the subject is viewed three-dimensionally.
FIG. 7 is an external view of a stereoscopic camera for taking the above-described stereoscopic photographs. The stereoscopic camera is composed of the main body 1 provided with a finder 2 and a shutter button 3, and two photographing lenses 4, 5 provided on the front surface of the main body 1 with an interval of about 30 mm between the two lenses 4, 5. A subject to be taken is positioned through the finder 2 and taken on the film mounted on the main body 1 through the photographing lenses 4, 5 by pressing the shutter button 3. Two images caught from different angles are thus projected on the film.
In another type of stereoscopic camera, the two photographing lenses 4, 5 have different object distance ranges; one is in focus in a short range and the other is in focus in a long range. Furthermore, the aperture of the stop for a short range is made smaller than the aperture of the stop for a long range so as to increase the depth of field. According to this type of camera, two stereoscopic photographs which are in focus in a short range and in a long range, respectively, are obtained. These two stereoscopic photographs enable the subject which is in focus in a wide range to be viewed three-dimensionally.
Since the conventional stereoscopic camera has the two photographing lenses 4, 5, as described above, two independent shutter mechanisms are provided for the photographing lenses 4, 5. The shutter leaves provided at the respective opening portions of the two shutters are simultaneously operated for a predetermined time by the respective shutter mechanisms so as to expose the film to a predetermined amount of light and to simultaneously photograph the same subject on two frames. Since two mechanisms are used to operate the shutter leaves simultaneously, the mechanisms become complicated and they are wasteful from the point of view of cost.
In the case of a simple (disposable) stereoscopic camera, it is necessary to simplify the mechanism as much as possible.
The applicant of the present invention has proposed a shutter which is capable of simultaneously operating the shutters at the two photographing portions by one leaf integrally connecting two shutter leaves. However, in the above-described type of camera in which the two photographing lenses 4, 5 are in focus in different photographing ranges, since the apertures of the spots are different in the two photographing portions, the quantity of incident light is different in the two photographing portions.